Composition comprising salt of acyl glutamate as primary surfactant or primary anionic surfactant

ABSTRACT

The present invention relates to compositions which comprise salt of acyl glutamate as primary surfactant or primary anionic surfactant and which compositions are clear, low pH isotropic composition.

FIELD OF THE INVENTION

The invention relates to personal care compositions. The compositionsare preferably aqueous-based, isotropic, personal care compositions. Thecompositions are preferably mild (defined for example by low percentzein dissolved relative to harsher compositions). Preferably, thecompositions have good foam volume (a signal of cleansing to manyconsumers) and are stable. Preferably, the compositions are clear at apH of 6.5 and lower, preferably at 6.0 and lower (generally the pH ofthe composition may be from about 3 to 6.5). Preferably the pH is fromabout 3.5 to 6.0, more preferably from about 3.5 to 5.5, more preferably4.0 to 5.5.

BACKGROUND OF THE INVENTION

Synthetic detergents, such as cationic, anionic, amphoteric, non-ionicsurfactants, are widely used in personal care cleaning compositions.Anionic surfactants generally exhibit superior cleansing and foamingproperties and are thus typically incorporated into such compositions.Anionic surfactants, however, also tend to be harsh on the skin.

Since consumers desire milder compositions (i.e., compositions which arenot as harsh and irritating on skin and skin proteins), it is known toreplace some anionic surfactant with other surfactants (e.g., nonionicand/or amphoteric surfactants). Another approach is to associate anionicsurfactants with amphoteric or cationic compounds to create surfactantcomplexes (see U.S. Pat. No. 4,443,362). Often these compositions sufferin foaming and/or cleansing performance.

Another approach for providing mildness is to use milder anionicsurfactants. Among such mild anionic surfactants that can be used areN-acylamino acids and their salts. The paper “Surface ActiveN-Acylglutamate: Preparation of Long Chain N-Acylglutamic Acid” (M.Takehaka et al.; Journal of the American Oil Chemists Society, Vol. 49,p. 157 ff) cites JP Patent No. 29444 (1964) according to which acylglutamates are said to alleviate skin irritations caused by otheranionic surfactants such as alkylbenzene sulfonates.

As seen in U.S. Pat. No. 6,703,427 to Schmucker et al., such acylaminoacids are contemplated as co-surfactants to alleviate harshness ofprimary anionic surfactants. By themselves, as the primary surfactant (a“primary surfactant” is one which is present at a level of 50% or moreof all surfactant) in a surfactant cleansing system (as is preferred forcompositions of the invention), or as the primary anionic surfactant (asa “primary anionic surfactant”, the surfactant is present at 50% or moreof all anionic surfactants; however, surfactants other than anionicsurfactants may in total comprise greater than 50% of the entiresurfactant system or less than 50% of the system), such surfactant wouldbe expected to be deficient in foam and/or cleansing relative to use ofother anionic surfactants in the same composition. Further, acylaminoacids are difficult to solubilize at lower pH ranges because themolecule will tend to precipitate. It would generally not becontemplated thus to use acylamino acids such as glutamate at a low pHand, typically, salt of glutamate does precipitate at about a pH of 5.5and lower. As such, such glutamate salt molecules would not becontemplated for use in isotropic liquids (where solubility is requiredto ensure good clarity) at any significant level. In particular, theywould not be contemplated for use as a primary surfactant, or as aprimary anionic surfactant and where, simultaneously, the amount ofglutamate is equal to or greater than, preferably greater than, anyother single surfactant present. That is, according to our invention, ifthe salt of glutamate is primary anionic surfactant but the total sum ofnon-anionic surfactants is greater than that of anionic surfactant, thesalt of glutamate must be present in an amount equal to or greater thanany other surfactant present. It is preferred that the glutamate salt bepresent as the primary surfactant.

It would further not be contemplated to use acyl glutamate (unlessspecified otherwise, we use the term “glutamate” or “acyl glutamate” tomean the salt of the glutamate) as a primary surfactant or as a primaryanionic surfactant (where glutamate is simultaneously present in anamount equal to or greater than any other single surfactant present),because glutamate does not structure (e.g., self-structure) as readilyas other surfactants and therefore can make it more difficult to suspendparticles and other benefit agents. As applicants have noted in aco-pending application, it is not readily apparent how to structure withexternal structurants while maintaining a relatively clear, isotropicliquid, particularly at a low pH (e.g., of 6.5 and lower, preferably 6.0and lower). Applicants have filed a co-pending application relating tocompositions where glutamate is the primary surfactant (and bydefinition the primary anionic surfactant) and in which specificstructuring polymers are used to provide enhanced structuring of theliquids while maintaining desired clarity (at low pH of 6.5 and lower,preferably of 6.0 and lower, preferably of 4.0 to 6.0, more preferably4.0 to 5.1).

In short, because acyl glutamate surfactants are not the type of anionicsurfactants which provide superior foaming, because they do not readilysolubilize (at lower pH), and because they do not self-structure as wellas other anionics, such surfactants would not have been considered foruse in a low pH (pH of 6.5 and lower) liquid cleansing composition asthe primary surfactant; or as the primary anionic surfactant, but wherethe amount of glutamate is equal to or greater than any other singlesurfactant present. In particular, they would not be contemplated foruse as primary or primary anionic surfactant in aqueous-based cleansingcompositions while retaining the ability to maintain good stability andclarity values.

Unexpectedly, applicants have found that it is possible to formulate lowpH, aqueous-based, isotropic compositions (which stay clear and stable)in which acyl glutamate is primary surfactant (preferred systems); orprimary anionic surfactant and simultaneously present in an amount equalto or greater than any other single surfactant present. Preferably, thepH of the composition is 6.5 and lower. More preferably of pH is 3.5 to6.0. More preferably, pH is 3.5 to 5.5 and most preferably 4.0 to 5.5,even more preferably 4.0 to 5.1. Preferably, the composition is visiblyclear (isotropic). Preferably, the composition is a single phase (singlephase which is isotropic), clear composition where clarity is defined byan absorbance value of 1.0 or lower, preferably 0.5 or lower (e.g.,0.01-0.5), more preferably 0.2 and below, when measured at wavelength of550 nm.

Further, applicants have found that, when the amount of shorter chainglutamate (as a percent of all glutamate) is minimized (to ensure goodfoam) and the percent of glutamate relative to co-surfactant ismaximized (saving on cost of use of co-surfactant while surprisinglymaintaining low pH, clear, one phase isotropic compositions), preferredcompositions are found. In preferred systems, glutamate is the primarysurfactant (present at level of 50% or more, preferably 55% or more ofall surfactant). Preferred systems comprising glutamate and particularco-surfactants are also disclosed.

In a co-pending application, applicants disclose compositions in whichspecific polymers can be used to further ensure that stable, isotropicliquids are formed at relatively low pH (pH of 6.5 and lower, preferablypH of 6.0 and lower, preferably pH of 5.5 and lower) also whilemaintaining defined level of clarity. Such stable and clear compositionswould not be expected to form in systems where glutamate is the primarysurfactant, or the primary anionic surfactant while simultaneouslypresent in an amount equal to or greater than any other singlesurfactant present.

A variety of compositions have been disclosed where glutamate isdisclosed broadly.

In U.S. Pat. No. 6,284,230 to Sako et al. a broad number of surfactants,including glutamates are said broadly to be able to be used as primaryanionic surfactant. From the examples however, it is clear that whereglutamate is used (Examples I-V), it is neither the primary surfactant(ammonium sulfate is in Examples I-V) nor is it the primary anionicsurfactant. In Example VI, sarcosinate (different acyl amino acid with asingle carboxylic acid group) is the primary surfactant. Never is anacyl amino acid having two carboxylic acid groups (such as glutamate)used as primary surfactant or as primary anionic surfactant in which theglutamate is used in an amount equal to or greater than any other singlesurfactant present.

US 2004/0258807 and US 2011/016506 are two other examples of referencesdisclosing glutamates broadly but again it is clear that glutamates arenever used as primary surfactants; or as primary anionic surfactant andwhere glutamate is simultaneously present in an amount equal to orgreater than any other single surfactant present in the composition.

US 2005/034895 shampoo compositions comprise surfactant, microbiologicalcontrol agent, rheological additive, conditioning agent and solubilizer.The surfactant compositions include mixtures of glutamate and othersurfactants (see Examples 2-5), but glutamate is never primarysurfactant or primary anionic where it is used in amounts equal to orgreater than any other single surfactant in the composition.

WO 2010/069500 discloses in Example 1, Composition E, a compositionhaving 3.5% glutamate, 3.5% sarcosinate, 8.5% betaine and 2.5%glucoside. In this composition glutamate is a primary anionic (it ispresent at level of 50% of anionic), but is not present in an amountequal to or greater than any other single surfactant present (e.g.,betaine is single greatest surfactant present). It is also not theprimary surfactant.

The present invention, as noted, requires the glutamate be eitherprimary surfactant (preferred embodiment); or present as primary anionicsurfactant while simultaneously being used in an amount equal to orgreater than, preferably greater than, any other single surfactantpresent in the composition. For reasons noted above, formation of suchsystem would not be contemplated because such systems where glutamate isused (especially as primary surfactant) in such relatively large amountswould have been thought to compromise the formation of compositionswhich are clear (isotropic), foam well, and are stable.

SUMMARY OF THE INVENTION

The present invention relates to compositions comprising:

-   -   1) 0.5-35% of a surfactant system wherein the anionic surfactant        is present at 0.5 to 25%, preferably 1 to 15% by wt. of the        total composition and where        -   a) the salt of acyl glutamate is present at 50% or greater            of all the surfactant present (“primary surfactant”); or        -   b) is present at level of 50% or more of the anionic            surfactant (preferably the salt of acyl glutamate comprises            greater than 50% by wt. of the anionic, more preferably            greater than 60% by wt. of total anionic) and simultaneously            is present in an amount equal to or greater than any other            single surfactant present in the composition (“primary            anionic surfactant”);    -   2) 0% to 20%, preferably 0.5 to 15% by wt. of a co-surfactant        selected from the group consisting of nonionic, cationic and        amphoteric surfactant and mixtures thereof (preferably, the        co-surfactants comprise amphoteric surfactant, optionally        further comprising nonionic; preferably amphoteric comprises        1-10% by wt. of total composition);    -   3) optionally, 0 to 30%, preferably 0.1-10%, more preferably        0.1-5% of a skin or hair benefit agent; and    -   4) balance water        -   wherein pH is 6.5 and lower, preferably wherein pH is 6.0            and lower, more preferably, wherein pH is 5.5 and lower,            more preferably where pH is 5.1 and lower.    -   A preferred pH range is about 3.5 to about 5.5, preferably 4.0        to 5.5, especially 4.0 to 5.1.

With regard to use of optional oil or emollient of component (3),applicants' first note that the invention may be defined as a surfactantchassis which itself is based on acyl glutamate as primary surfactant orprimary anionic surfactant. The surfactant chassis is preferably astable, single phase, isotropic, optically clear composition. However,when certain optional components (e.g., certain oils or emollients) areadded to the surfactant chassis, these may not be completely misciblewith the stable, isotropic, surfactant chassis and may render theresulting full formulation anisotropic (e.g., the composition is nolonger “clear”).

Thus, the invention may comprise a full formulation which contains nooil or emollient; or which contains a sufficiently low amount of oil oremollient; or which contains an oil or emollient which is miscible withthe surfactant chassis so as not to become anisotropic as noted above.This formulation is a stable, single phase composition which is clear(isotropic) as defined by an absorbance value of 1.0 or lower at definedwavelength.

The compositions of the invention could preferably comprise immisciblebenefit agent. The invention also comprises a full formulation which isanisotropic (not optically clear) but which is formed from thecombination of (1) a stable, single phase surfactant chassis, which ispreferably optically clear; and (2) optional ingredient(s) present insufficient amount to render the final full formulation anisotropic. Afinal anisotropic formulation which is not formed from the stable,single phase, optically clear surfactant chassis is not considered partof the subject invention. Specifically, a composition which isanisotropic before addition of, for example, emollient or oil is notpart of the invention.

Preferably, compositions of the invention (whether isotropic at fullformulation or isotropic at chassis formation and anisotropic uponaddition of certain benefit agents) are, or are formed from single phaseisotropic systems. Preferably, the compositions (again, as finalcomposition, or as isotropic chassis before addition of potentialanisotropic forming benefits agents) maintain optical clarity.Preferably the compositions (as final isotropic composition or isotropicchassis) are single phase systems which maintain optical clarity asdefined herein. Preferably the single phase, optically clear systems arestable and maintain a single, optically clear phase under ambientconditions (about 25° C.) over a period of one month or longer,preferably up to about one (1) year.

In typical, preferred compositions of the invention, the amount ofglutamate surfactant is equal or is in excess of all other surfactants(“primary surfactant”); it may also be present at 50% or more of anionicand simultaneously in amount equal to or greater than any one othersingle surfactant (“primary anionic surfactant”). Even if the sum ofsurfactants other than anionic form more than 50% of the surfactantsystem, glutamate must be present in an amount equal to or greater thanany other single surfactant. It is preferred, however, that glutamate bethe primary surfactant. It is also preferred to maximize the amount ofglutamate used and minimize use of cosurfactants.

Some compositions of the invention may contain 0 to 10% by wt.,preferably 0.1 to 10% by wt., more preferably 0.5 to 7% by wt. ofstructurant. Such structurant may be water soluble or water dispersiblepolymer which can be a cationic, anionic, amphoteric or nonionic polymerfor enhancing viscosity and stability of the cleanser and is selectedfrom the group consisting of carbohydrate gums; modified andnon-modified starch granules; polyacrylate and methacrylate polymer andcopolymer; cationic polymers including cationic modified polysaccharide,cationic modified cellulose and synthetic cationic polymers. Inapplicants co-pending application, particular polymers are disclosedwhich define an enhanced stability benefit. As indicated, thestructurant need not be present although it is preferred for stabilizingthe composition and helping to suspend, especially to suspend oilsoluble emollients. In a related co-pending application, applicantsclaim compositions comprising specific structurants which surprisinglymaintain relatively clear (isotropic) liquids which are stable, all atdefined low pH range.

Compositions of the invention may comprise water-soluble or oil-solubleskin or hair benefit agents. These may be present at levels of 0-30%,preferably 0.1-20% by wt., more preferably 0.1 to 10% by wt. totalcomposition. Some compositions comprise water-soluble polyhydroxyalcohols. Preferred water soluble skin benefit agents include glycerin,sorbitol and polyalkylene glycols (a preferred polyalkylene glycol ispolyethylene glycol) and mixtures thereof. Preferably, oil solubleemollients comprise 30% or less, preferably 10% or less, preferably 5%or less (e.g., 0.1 to 5% by wt.) of composition. In some preferredembodiments, oil soluble emollients or oils are absent.

In the absence of immiscible benefit agents (such as oil solubleemollient or oils), the final compositions are clear (isotropic). Theymay remain so if the quantities of immiscible ingredients aresufficiently small. However, even though the surfactant chassis isclear, the invention also contemplates full formulations which may beanisotropic but are formed from the combination of isotropic surfactantchassis and sufficient amounts of immiscible benefit agent to render thefull formulation anisotropic.

DETAILED DESCRIPTION OF THE INVENTION

The invention relates to low pH cleansing compositions, preferablyaqueous-based and clear, wherein salts of acyl glutamate are present as“primary surfactant”; or, where the glutamate salts are “primary anionicsurfactants” (although non-anionic may be present at greater than 50% ofall anionic surfactant) and are simultaneously present in an amountequal to or greater than any other single surfactant present. Whenglutamate is not present in an amount equal to or greater than any othersingle surfactant, such composition is not intended to be encompassed bycompositions of the invention.

Whether or not the glutamate is primary surfactant, or primary anionicsurfactant while simultaneously present in amounts equal to or greaterthan, preferably greater than any other single surfactant, it is seenthat glutamate necessarily comprises 50% or greater of all anionicsurfactant present and, as noted, is present in an amount equal to orgreater than, preferably greater than, any other single surfactant inthe composition. Because of the properties of glutamate noted above, itwould not have been previously contemplated to form low pH compositionswhere glutamate is primary surfactant or primary anionic surfactantwhile maintaining stable, single phase, clear (isotropic) formulations.In some preferred compositions, the amount of short chain glutamate (C₁₀or below) is minimized (to enhance foaming). In some preferredcompositions, particular structurants are used to enhance structuring(while maintaining clarity), even at very low pH. These single phase,isotropically clear compositions are also preferably stable as definedabove.

Although glutamate surfactants are milder than other anionicsurfactants, they do not typically foam or cleanse as well. Like allacylamino surfactants, acyl glutamates are also difficult to solubilizeat low pH and would therefore not be contemplated for use in low pH,clear (isotropic) compositions (i.e., lack of solubility would bebelieved to affect clarity), particularly at the relatively high levelsof glutamate surfactant required in the subject invention. This isespecially true for preferred systems where glutamate is the primarysurfactant.

Unexpectedly, applicants have now produced low pH, stable, clear(isotropic) compositions (as final formulation or as surfactant chassisprior to addition of anisotropic inducing agents) wherein glutamate isthe primary surfactant or primary anionic surfactant and present in anamount equal to or greater than any other single surfactant. Preferredcompositions maximize the amount of glutamate used (as percent of totalsurfactant) in order to minimize costly co-surfactant. Further,preferred compositions minimize the amount of shorter chain lengthglutamate used and thereby enhance foaming. Finally, in other preferredcompositions (as claimed in co-pending application), use of specificstructurants allow use of maximum amounts of glutamate in clear,single-phase compositions (as final composition or as surfactantchassis) and particularly at low pH (e.g., of 5.5 and lower, preferably5.0 and lower). In some preferred systems, the amount of benefit agent,particularly oil or oil soluble emollient, is minimized (0 to 30%,preferably 0 to 10%, preferably 0 to 5% by wt., preferably absent).

More specifically, compositions of the invention comprise:

-   -   1) 0.5 to 35% by wt. of total composition of a surfactant system        (surfactant chassis) wherein the anionic surfactant is present        at 0.5 to 25% by wt. of total composition and wherein salt of        acyl glutamate        -   a) is present at 50% or more, preferably 60% or more, more            preferably 65% or more of all surfactant present (“primary            surfactant”); or is present at 50% or more, preferably            greater than 50%, more preferably greater than 60% of the            anionic surfactant and is simultaneously present in amount            equal to or greater than any other single (non-anionic)            surfactant in the composition (“primary anionic            surfactant”); for purposes of this definition, if the            glutamate and the second anionic surfactant both comprise            50%, glutamate is still considered a “primary anionic            surfactant”; and        -   b) 0% to 20%, preferably 0 to 15% by wt. of a co-surfactant            selected from the group consisting of nonionic, cationic and            amphoteric surfactants and mixtures thereof; preferably            there is present amphoteric surfactant as 1-10% by wt. of            total composition. By co-surfactant is meant surfactant            separate from the glutamate and separate from any additional            anionic surfactant which defines component (a) above (i.e.,            although other anionic surfactants comprise part of            component (a) and are used in amount 50% or less of total            anionic, component (b) is concerned with surfactants which            are not anionic);        -   Depending on particular co-surfactants used (and to some            extent the chain length of glutamate salts), the amount            needed to optimize in a system with glutamate and            amphoacetate, the amount of amphoacetate to glutamate            required to maximize isotropic region can be in ratio of 1/7            (using mix of decanoyl and cocoyl glutamate) (e.g., 12.5%            amphoacetate to 87.5% glutamate; see Table 2) and higher or            even 1/1.7 (even more amphoacetate; using mix of decanoyl            and lauroyl, see Table 1) and higher (up to 1/1); by            contrast when using CAPHS or cocoyl betaine, less            co-surfactant can be used (e.g., ratio of 1/19 and higher,            see Tables 4 and 5 where stable regions are obtained at            about 5% CAPHS or cocoylbetaine to 95% glutamate) while            maximizing isotropic region.        -   The above are non-limiting examples of some co-surfactants            which may be used and, as noted, are not intended to limit            the invention in any way.    -   2) optionally 0 to 30%, preferably 0.1 to 20%, more preferably        0.1 to 10% by wt. of a skin or hair benefit agent; preferably        the benefit agent is an oil-soluble emollient or moisturizing        oil (although water-soluble agents may also be used). Preferably        it is petrolatum or silicone. Also preferably, the oil is a        vegetable or triglyceride oil. Preferred oils include sunflower        seed oil and soybean oil. Other oils are noted below. Preferably        the emollient can be an ester of long chain (e.g., 014-030)        fatty acid such as isopropyl palmitate or cetyl lactate;        combinations of any of the above are preferred; and    -   3) balance water and other ingredients as defined below wherein        pH of composition is 6.5 and below, preferably 6.0 and below,        more preferably 5.5 and below; preferably pH is 3.5 to 6.0, more        preferably 3.5 to 5.5, more preferably 4.0 to 5.5.

As indicated, the amount of glutamate may be such that it is the primarysurfactant overall; or glutamate may be the primary anionic surfactant,while the amount of surfactants other than anionic is in excess of theglutamate. Where glutamate is the “primary anionic surfactant”, but thesurfactant system has less than 50% anionic surfactant overall,glutamate must be present in amount equal to or greater than any othersingle surfactant present in the composition.

Further, the compositions of the invention are clear (isotropic)one-phase solutions. That is, there is one single clear phase (ratherthan one phase which is clear as part of a multi-phase solution). Thephase is stable (does not break into multi-phases). By clear is meanthaving absorbance value of 1.0 or lower, preferably 0.5 or lower, morepreferably 0.2 and below when measured at wavelength of 550 nm.

If benefit agent component (2) is not completely miscible in thesurfactant chassis of (1), the composition may be anisotropic. However,the invention is defined either by presence of component (2) which ismiscible so that final formulation is isotropic or, by final anisotropiccomposition which was formed from combination of isotropic chassis ofcomponent (1) and benefit agent of component (2). The key to invention,however, is formation of final composition (isotropic; or anisotropicfrom an isotropic chassis defined by components (1) and (3)) having a pHand stability, as well as clear, one-phase isotropic characteristicsdefined.

Surfactant System

Anionic Surfactant

A key to the invention is that there is present 0.5 to 35% by wt. oftotal composition of a surfactant system wherein anionic surfactantcomprises 0.5 to 25% by wt. of total composition and wherein salt ofacyl glutamate comprises 50% or more of all surfactant (“primarysurfactant”); or 50% or more, preferably 60% or more by wt. of the totalanionic surfactant present (even if anionic overall is less than 50% oftotal surfactant), and is present in an amount equal to or greater thanany other single surfactant in the composition. Preferably anionicsurfactant comprises 1-15% by wt. of total composition, more preferably2 to 12% of total composition. In some compositions, anionic comprises5-12% by wt. of the total composition and surfactants which are notanionic comprise 1 to 7% by wt. of the composition. The amount ofglutamate should always be maximized and as noted, even if othersurfactants are present in amounts greater than anionic (e.g., whenglutamate is not the “primary surfactant”), glutamate is present at 50%or more of anionic surfactant and is present in an amount equal to orgreater than any other single surfactant present.

The salt of acyl glutamate used in the composition of this invention hasa structure as follows:

(It is noted that one or the other structures will occur at pH levels ofthe invention (pH 6.5 and below, preferably 3 to 6.5) and that at higherpH (e.g., 8 or 9), some di-salt is also present),

where R is alkyl or alkenyl group (generally saturated although someunsaturated, for example, oleoyl, may be present) having 8 to 20carbons, preferably 8 to 16 carbons, more preferably 10 to 14 carbons.Preferably, R is predominantly a mixture of C₁₀ to C₁₄. As indicatedabove, for preferred levels of foaming, it is preferable to minimize theamount of shorter chain length (e.g., C₈ and C₁₀) and to maximize longerchain length, e.g., C₁₂-C₂₀, preferably C₁₂-C₁₈. Although C₁₀ should beminimized, it will be seen, at least in some embodiments of theinvention, that ratio of C₁₀ to C₁₂ should be at least 1/5, possibly 1/3and higher (in part depending on co-surfactant used with glutamatesalts) to ensure isotropic formation. Preferably ratio should be nohigher than 1 to 1, regardless of the co-surfactant used (if any) withglutamate salts.

As used in the examples, a cocoyl chain length distribution is typicallydefined as follows: 13% C₈-C₁₀, 50% C₁₂, 18% C₁₄, 8% C₁₆, and 11% ≧C₁₈,(http://coconutboard.nic.in/English-Article-Gopalakrishna-CFTRI.pdf), aspreferred here.

M is a solubilizing cation such as, for example, sodium, potassium,ammonium or substituted ammonium. It is preferred that the cation issodium or potassium, more preferably sodium. Sodium salt is preferred.

The pH of the overall composition is typically 6.5 and lower, preferably6.0 and lower. Preferably pH is 3 to 6.5 and more preferably 3 to 6.More preferably, pH is 3.5 to less than 6, preferably 3.5 to 5.5, morepreferably 4.0 to 5.5, even more preferably 4.0 to 5.1.

The pKa of the salt of acyl glutamate is relatively low (about 5).Applicants have surprisingly found that the relatively large amounts ofglutamate used can be solubilized thereby allowing to take advantage ofthe mildness of this anionic surfactant relative to other anionicsurfactants.

Further, surprisingly large amounts of glutamate can be solubilized atlow pH, thereby permitting formation of clear, one-phase isotropiccompositions which are also mild.

Clear and mild cleansers are seen as highly desirable by consumers. Byclarity, applicants mean having absorbance value of 1.0 or lower,preferably 0.5 or lower, even more preferably 0.2 or lower when measuredat wavelength of 550 nm. As indicated above, clarity values define thesurfactant chassis and water. Composition may maintain clarity (stayisotropic) upon addition of benefit agent but, even if final compositionis anisotropic, if the initial chassis was isotropic as defined, itfalls within definition of the invention.

While the acyl glutamate salt may be used as the only anionic surfactantin the total composition, it is desirable to use other anionicsurfactants, subject to the levels defined here. One preferredco-anionic (as opposed to co-surfactant 1(b)) is sarcosinate (alkyl saltof C₁₀-C₁₄ acyl sarcosinate is a preferred sarcosinate, where salt isdefined as in M above). Another preferred co-anionic is a taurate. Asalt of C₁₀-C₁₄ acyl taurates (e.g., sodium cocoyl methyl taurates) ispreferred. Generally, it is preferred not to use salts which would tendto precipitate at lower pH values. Thus, it is preferred to minimize,for example, the amount of acyl glycinate (<1.0%, preferably <0.5%,preferably absent altogether).

Generally, sarcosinate have formula:

R² CON(CH₃)CH₂CO₂M;

Taurates have formula:

R²CONR³CH₂CH₂SO₃M,

where R³ is methyl;

Glycinates have formula:

R²CONHCH₂CO₂M

where R² above is alkyl or alkenyl having 8 to 22 carbons, preferably 12to 18 carbons; and

M is solubilizing cation as defined above.

Compositions of the invention may have low levels of alkyl ethersulfates, for example, sodium lauryl ether sulfate. By low is meant <20%of anionic, preferably <10%, more preferably <5%. In some embodimentsthe compositions have <0.5% alkyl ether sulfate and in some there issubstantially no alkyl ether sulfate. These types of sulfates arepreferably minimized because they are less mild than other surfactants.

Co-Surfactant

A second component of the invention may comprise 0% to 20%, preferably0.5 to 15% by wt. of total composition of a co-surfactant selected fromthe group consisting of non-ionic, cationic, and amphoteric surfactantand mixtures thereof.

Preferred co-surfactants are amphoteric or zwitterionic surfactant.Preferably the co-surfactant is amphoteric.

This general class of amphoteric detergents has the following generalstructure:

where R is an alkyl or alkenyl radical of 7 to 17 carbons or acarboxamido functional group of the general structure

where R₁ is an alkyl or alkenyl radical of 7 to 17 carbons and R₄ is analkyl, hydroxyalkyl, or carboxyalkyl radical of 1 to 3 carbons. R₂ andR₃ are each independently a proton, an alkyl, hydroxyalkyl, orcarboxyalkyl radical of 1 to 3 carbons, or is missing entirely, subjectto the following restraints. When R₂ and R₃ are each independently analkyl, hydroxyalkyl, or carboxyalkyl radical, the nitrogen in aquaternary amine and is a cationic charge center. When one of R₂ or R₃is an alkyl, hydroxyalkyl, or carboxyalkyl radical and the other is aproton or is missing entirely, the nitrogen is a tertiary amine. At a pHwell below the pKa of the tertiary amine, the other of R₂ or R₃ will bea proton and the amine will be a cationic charge center. At a pH wellabove the pK_(a) of the tertiary amine, the other of R₂ or R₃ will bemissing entirely and the amine will be a neutral charge center.

Preferred examples of amphoteric noted above includecocoamidopropylbetaine (CAPB), C₁₀-C₁₄ alkyl betaine, the salt ofC₁₀-C₁₄ alkyl amphoacetate (e.g. lauroamphoacetate) and mixturesthereof.

Another class of amphoteric detergents are the sultaines having thefollowing general structure:

where R is an alkyl or alkenyl radical of 7 to 17 carbons or acarboxamido functional group of the general structure

where R₁ is an alkyl or alkenyl radical of 7 to 17 carbons and R₄ is analkyl, hydroxyalkyl, or carboxyalkyl radical of 1 to 3 carbons. R₂ andR₃ are each independently an alkyl, hydroxyalkyl, or carboxyalkylradical of 1 to 3 carbons, so that the nitrogen in a quaternary amineand is a cationic charge center. A preferred amphoteric surfactant ofthis class is cocamidopropyl hydroxy sultaine (CAPHS), lauramidopropylhydroxy sultaine (LAPHS), or lauryl hydroxy sultaine (LHS).

A preferred combination of the invention is salt of glutamate and saltof sarcosinate as anionic surfactants in combination with salt ofamphoacetate (preferably C₁₀-C₁₄ amphoacetate) as co-surfactant. Apreferred combination comprises 3-8% by wt. total composition salt ofglutamate, 1-3% by wt. total composition salt of sarcosinate (where,preferably, glutamate is the primary surfactant or primary anionic asdefined above) and 3-8% by wt. total composition salt of amphoacetate(particularly alkali metal salt of acyl amphoacetate). As previouslynoted, glutamate must be present in an amount equal to or greater thanany other single surfactant present.

A key aspect of compositions of the invention is that (as full isotropiccomposition, or as surfactant chassis prior to forming composition) theyare stable, clear, one-phase isotropic liquids, particularly at pHvalues of 6.5 and lower, preferably pH of 3.5 to 6.0, more preferably3.5 to 5.5, more preferably 4.0 to 5.5.

The glutamate salts may comprise a mixture of chain lengths. Asindicated, it is typically preferably to minimize shorter C₈ and C₁₀lengths as these do not typically foam as well. Using a mixture of C₁₀and cocoyl also helps to extend regions of isotropic clarity compared tomixtures where only, for example, C₁₀ and C₁₂ are used. This suggeststhat some amount of C₁₄ to C₂₀ may also be preferred.

In some compositions, the surfactant system comprises a mixture of C₁₀and cocoyl glutamate together with alkali metal salts of amphoacetate.

Primarily, the invention is about the unexpected observation thatglutamate may be used as primary surfactant; or as primary anionicsurfactant and is simultaneously used in an amount equal to or greaterthan any other single surfactant present in the composition. Preferablyit is used as primary surfactant in low pH, aqueous-based single-phase,compositions having visual clarity. Even if added benefit agent causesformation of final anisotropic composition, the surfactant chassis,prior to addition of anisotropic forming agent, is isotropic. Because oftheir low pH solubility, it is thus possible to make a mild composition(acylamino surfactant being mild) which is also optically clear(isotropic). At the same time, because these are low pH compositions,they can provide antibacterial effect while avoiding use of certainantibacterial agents which are restricted in certain parts of the world.

Thus, anisotropic compositions (formed using glutamate-based isotropicchassis) with low pH and low pH compatible preservation systems areanother aspect of the invention.

Use of these milder glutamate surfactants at relatively high levels alsopermits that lesser amounts of cosurfactants (e.g., amphoacetate, CAPB)be used. It can be seen that amphoacetate maintains a wider isotropicregion than CAPB (Tables 1 & 2 versus Table 3). Similarly CAPHS and cocobetaine maintain a wider isotropic region than CAPB (Tables 4 and 5versus 3). This is important in particular for fully formulatedisotropic compositions.

When a mixture of C₁₀ and C_(coco) is used (see e.g. Table 2), which canbe preferred in this invention, compared to mixture of C₁₀ and C₁₂(Table 1) an isotropic region is achieved using lower amounts of C₁₀glutamate. That is, less C₁₀ is needed to achieve soluble region (whichalso helps with lather production). Systems with glutamate plusamphoteric co-surfactant are hence preferred (e.g., amphoacetate orcocoamidopropylbetaine). Non-ionic surfactant is a preferred additionalco-surfactant in a glutamate/co-surfactant system.

Our examples show that changing the distribution of the chain length onthe glutamate surfactant can also provide preferred isotropiccompositions. Thus, as use of glutamate is enhanced and the amount ofcosurfactant minimized, the amount of lower chain length (e.g., C₈, C₁₀)glutamate can be lessened while still obtaining clear isotropiccompositions at low pH. Using more of the higher chain length glutamate(e.g., C₁₂ to C₂₀) also helps maintain good foam values.

As indicated above, while C₁₀ should be minimized, depending on specificsurfactant systems, in some embodiments of the invention ratio of C₁₀ toC₁₂ should be at least 1/5, possibly 1/3 and higher (although preferablyno higher than 1/1) to ensure formation of isotropic compositions asdefined.

Preferred stable, isotropic compositions are those with a ratio ofC₁₀/C₁₂ acyl glutamate of about 1/3 and higher and with a ratio oflauroamphoacetate/acyl glutamate of about 1/1.7 and higher (up to 1/1).To ensure good foam performance and minimize costs, the ratio of C₁₀/C₁₂acyl glutamate is preferably 1/1 and lower (preferably above 1/3) andthe ratio of lauroamphoacetate/acyl glutamate should be 1/1 or lower.

There is thus the desired benefit achieved of preferred compositionswith enhanced glutamate (using less cosurfactant) and greater amounts ofhigher chain glutamate (better foaming, especially good since there isless co-surfactant). Again, enhanced foam benefit from compositionsbased on isotropic surfactant chassis is seen whether final formulationsare isotropic or anisotropic.

Preferably, the glutamates should be used in a concentration of ≧50% ofsurfactant system, more preferably ≧60%, more preferably >70%.

One composition which can be used comprises 50% glutamate and alkalimetal alkyl (C₈-C₁₄) amphoacetate, preferably lauroamphoacetate. Thecomposition may comprise a mixture of C₁₀ and C₁₂ or C₁₀ and C_(coco)glutamate (C_(coco) glutamate is glutamate with cocoyl chain lengthdistribution as defined above). Mixtures of C₁₀ and C_(coco) arepreferred if it is desired to minimize C₁₀ content since higher chainlengths typically provide better foaming. Such a mixture of C₁₀ andC_(coco) preferably has a C₈-C₁₀ chain length distribution whereinC₈-C₁₀ is present in an amount of more than 13%, preferably more than15% of all R groups on glutamate salt as defined above.

In addition to absolute amounts of co-surfactant (preferred tominimize), in some specific compositions we can define approximateminimum ratios of co-surfactant to glutamate needed to ensure isotropicformation. Thus, in amphoacetate/glutamate systems, the ratio ofamphoacetate to glutamate is preferably about 1/7 and higher (up to 1/1)to maximize isotropic region. This may depend on chain lengths ofglutamate and another preferred system is where mix of decanoyl andlauroyl glutamate is used and ratio of amphoacetate to glutamate is 1 to1.7 and higher (preferably glutamate is primary surfactant overall).

Preferred stable, isotropic compositions are those with a ratio ofC₁₀/C_(coco) acyl glutamate of about 1/3 and higher and with a ratio oflauroamphoacetate/acyl glutamate of about 1/7 and higher. To ensure goodfoam performance, minimize costs, and observe an enhanced viscosity, theratio of C₁₀/C_(coco) acyl glutamate is preferably 1/1 and lower(preferably about 1/3 and above) and the ratio of lauroamphoacetate/acylglutamate should be 1/1.7 or lower.

Another composition that may be used (although not preferred) comprises50% glutamate and betaine, for example, cocoamidopropyl betaine. In suchsystems, glutamate comprises ≧60% of the surfactant system, morepreferably 75%, more preferably ≧80%. In a preferred system of theinvention the ratio of amphoacetate to glutamate can be 1/19 and higher(preferably glutamate is primary surfactant). In such system, lessco-surfactant is required to optimize isotropic region (e.g., comparedto use of cocamidopropylbetaine).

Similarly, another preferred embodiment comprises a surfactant systemwhich is a mix of CAPHS and glutamate and where ratio of CAPHS toglutamate salts is as low as 1/19 and higher (up to 1/1). Again, it isseen that less co-surfactant is needed to optimize isotropic regioncompared to CAPB.

Generally, preferred compositions are those in which salt of glutamateis selected from the group consisting of C10, C12 and C_(coco) glutamateand mixtures thereof. In a mixture comprising C_(coco), mixturepreferably has a C₈-C₁₀ chain length distribution wherein C₈-C₁₀ ispresent in an amount of more than 13%, based on all R chain lengths onthe glutamate salts. In such general composition, preferablyamphoacetate is co-surfactant and preferably the ratio of amphoacetateto glutamate is 1/7 and higher, preferably 1/7 to 1/1. Another preferredco-surfactant is one selected from the group consisting of betaine,sultaine and mixtures thereof wherein the ratio of co-surfactant toglutamate is 1/19 and higher, preferably 1/19 to 1/1

Preferred stable, isotropic compositions are those with a ratio ofC₁₀/C_(coco) acyl glutamate (using CAPHS, less co-surfactant is neededto obtain isotropic region compared to certain other co-surfactants,e.g., CAPB or amphoacetate) of about 1/7 and higher and with a ratio ofCAPHS/acyl glutamate of about 1/19 and higher. To ensure good foamperformance, minimize costs, and observe an enhanced viscosity, theratio of C₁₀/C_(coco) acyl glutamate is preferably 1/1 and lower and theratio of CAPHS/acyl glutamate is prefeably 1/1 or lower.

Skin or Hair Benefit Agents

In the same composition of the invention, 0 to 30% by wt., preferably0.1 to 10%, more preferably 0.1 to 5% by wt. skin or hair benefit agentis used. As the skilled person will understand, in the presentcomposition, the benefit agent is a different compound than thesurfactants indicated under the surfactant system. Hence, preferably,the benefit agent preferably is not a surfactant. Preferably the benefitagent is an oil soluble emollient or moisturizing oil. These aremolecules which increase hydration by various mechanisms which mayinclude prevention of water loss (occlusive agents), attracting moisture(humectants); or which restore natural moisturizing factors to the skin(e.g., amino-lipids). Preferred moisturizers include petrolatum andsilicone. Preferably, moisturizer is a vegetable or triglyceride oil.Preferred oils include sunflower seed oil and soybean oil. Themoisturizer may be an ester of long chain [C₁₄-C₃₀] fatty acid, such asisopropyl palmitate.

Some naturally restorative agents and moisturizers include:

-   -   a) vitamins such as vitamin A and E, and vitamin alkyl esters        such as vitamin C alkyl esters;    -   b) lipids such as cholesterol, cholesterol esters, lanolin,        sucrose esters, and pseudo-ceramides;    -   c) liposome forming materials such as phospholipids, and        suitable amphophilic molecules having two long hydrocarbon        chains;    -   d) essential fatty acids, poly unsaturated fatty acids, and        sources of these materials;    -   e) triglycerides of unsaturated fatty acids such as sunflower        oil, primrose oil, avocado oil, almond oil;    -   f) vegetable butters formed from mixtures of saturated and        unsaturated fatty acids such as Shea butter;    -   g) minerals such as sources of zinc, magnesium and iron; and    -   h) silicone oils, gums, modifications thereof such as linear and        cyclic polydimethylsiloxanes, amino, alkyl and alkyl aryl        silicone oil.

Water soluble benefit agents may also be used. Preferred water-solubleagents include glycerin, sorbitol, polyalkylene glycols and mixturesthereof.

If used, depending on amount and miscibility of benefit agent in theisotropic surfactant chassis, the chassis may still maintain clarity.However, even if benefit agent renders chassis anisotropic, the low pHand foaming benefits discussed above are still retained.

Although compositions of the invention do not require externalstructurants, when oil soluble benefits as noted above are used, it ispreferably to use structurants.

Structurant

Preferably, compositions of the invention comprise 0.1 to 10% by wt.,preferably 0.5 to 7% by wt. of a structurant. The structurant may be awater soluble or water dispersible polymer which can be a cationic,anionic, amphoteric or nonionic polymer for enhancing viscosity.

Examples of water soluble/or dispersible polymers useful in the presentinvention include the carbohydrate gums such as cellulose gum,microcrystalline cellulose, cellulose gel, hydroxyethyl cellulose,hydroxypropyl cellulose, sodium carboxymethylcellulose, hydroxymethyl orcarboxymethyl cellulose, methyl cellulose, ethyl cellulose, guar gum,gum karaya, gum traganth, gum Arabic, gum acavia, gum agar, xanthan gumand mixture thereof; modified and non-modified starch granules withgelatinization temperature between 30 to 85° C., and pregelatinized coldwater soluble starch; polyacrylate; Carbopols; alkaline solubleemulsions polymer such as Aculyn 28, Aculyn 22 or Carbopol Aqua SF1;cationic polymers such as modified polysaccharides including cationicguar available from Rhone Poulenc under the trade name Jaguar 013S,Jaguar 014S, Jaguar 017, or Jaguar 016, BF Guar 017 from Lamberti, AquaD4091 or Aqua D4051 from Aqualon; cationic modified cellulose such asUCARE Polymer JR30 or JR 40 from Amerchol; N-Hance 3000, N-Hance 3196,N-Hance CPX215 or N-Hance GPX 196 from Hercules; synthetic cationicpolymer such as Merquat 100, Merquat 280, Merquat 281 and Merquat 550 byNalco; cationic starches, e.g., StaLok® 100, 200, 300 and 400 made byStaley Inc.; cationic galactamannans based on guar gum of Galactasol 800series by Henkel, Inc.; Quadrisect Um-200, and Polyquaternium-24.

Gel forming polymers such as modified or non-modified starch granules,xanthan gum, Carbopol, alkaline-soluble emulsion polymers and cationicguar gum such as Lamberti BF Guar 017, and cationic modified cellulosesuch as UCARE Polymer JR 30® or JR 40® are particularly preferred forthis invention.

A preferred structuring copolymer is the polymerization product (e.g.,additive polymerization product) of (1) a first ethylenicallyunsaturated monomer; (2) a second ethylenically unsaturated monomer; (3)(meth)acrylate monomer and (4) associative monomer (generally random instructure; preferably copolymers are linear).

The first monomer of (1) may be di-acid of formula:

HOOC—CR¹═CR²—OOOH   (I),

-   -   a cyclic anhydride precursor of diacid (I), the anhydride having        the formula:

-   -   and combinations thereof,

wherein R¹ and R² are individually selected from H, C₁-C₃ alkyl, phenyl,chlorine and bromine and, in one or more embodiments, are preferablyindividually selected from H and C₁-C₃ alkyl.

Preferred monomers include maleic acid and maleic acid anhydride. It maycomprise 0 to 10%, preferably 0.1 to 5% by wt. on total wt. of monomercharge.

The second monomer (2) can be acrylic acid, methacrylic acid andcombinations thereof. It can be used at 15-60% by wt. based on totalmonomer charges.

The third (meth)acrylate monomer can be C₁ to C₈ alkyl esters of acrylicacid, C₁ to C₈ alkyl alkyl esters of methacrylic acid and combinationsand can be 30-75% by wt. based on total monomer charge.

-   -   a) The associative monomer has the formula:

R⁴—CH═C(R³)—C(O)—O—(R⁵O)_(a)—R⁶   (III)

-   -   wherein:        -   R³ and R⁴ are independently selected from H and C₁₋₃ alkyl,        -   each R⁵O is independently an oxyalkylene unit having from 2            to 4, preferably from 2 to 3 carbon atoms,        -   R⁶ is selected from:            -   linear and branched alkyl having from 8 to 40,                preferably from 8 to 30, more preferably from 10 to 22                carbon atoms, and            -   alkaryl, the alkyl group of which has from 8 to 40,                preferably from 8 to 30, more preferably from 10 to 22                carbon atoms, such alkyl group being linear or branched,                said alkaryl preferably being alkylphenyl; and        -   a has a value of from 6 to 40, preferably from 15 to 35,            most preferably from 20 to 30.

Of particular interest in one or more embodiments is an associativemonomer of the formula:

CH₃[CH₂]_(b)—CH₂—[OCH₂CH₂]_(a)—O—C(O)C(R³)═CH(R⁴)   (IV)

in which R³, R⁴ and a are as described above, and b has a value of from6 to 38, preferably from 6 to 28, and more preferably from 8 to 20.

In the Formula III and Formula IV monomers, R³ is preferably a methylgroup and R⁴ is preferably H. In the above described associativemonomers, a and b represent the number of their respective oxyalkyleneand —CH₂— repeat units and generally are integers. In one or moreembodiments of interest a is greater than or equal to b.

The associative monomer may be employed in amounts of from 1 to about 25wt. %, preferably from 2 to 20 wt. %, and more preferably from 2 to 15wt. %, based on total monomer added. In one or more embodiments ofparticular interest the amount of associative monomer employed is from 5to 12 wt. %, based on total monomer added.

In some compositions a structurant which has been found particularlyeffective to maintain clarity and stability is copolymer of thefollowing formula:

wherein a, b, c, d and e represent the percentage by weight that eachrepeating unit monomer is contained within the copolymer;

-   -   A is a polyacidic vinyl monomer selected from the group        consisting of maleic, fumaric, itaconic, citraconic and acid        combinations thereof and anhydrides and salts thereof; and    -   B is acrylic or methacrylic acid or a salt thereof;    -   C is a C₁-C₈ ester of acrylic acid or methacrylic acid;    -   D is an associative monomer of formula (VI)

-   -   wherein each R₂ is independently H, methyl, —C(═O)OH, or        —C(═O)OR₃;    -   R₃ is a C₁-C₃₀ alkyl;    -   T is —CH₂C(═O)O—, —C(═O)O—, —O—, —CH₂O—, —NHC(═O)NH—, —C(═O)NH—,        —Ar—(CE₂)_(z)—NHC(═O)O—, —Ar—(CE₂)_(z)—NHC(═O)NH—, or        —CH₂CH₂NHC(═O)—;    -   Ar is divalent aryl;    -   E is H or methyl;    -   z is 0 or 1;    -   k is an integer in the range of 0 to 30; and m is 0 or 1;    -   with the proviso that when k is 0, m is 0, and when k is in the        range of 1 to 30; m is 1;    -   (R₄O)_(n) is polyoxyalkylene, which is a homopolymer, a random        copolymer, or a block copolymer of C₂-C₄-oxyalkylene units,        wherein R₄ is C₂H₄, C₃H₆, C₄H₈, or a mixture thereof, and n is        an integer in the range of 5 to 250;    -   Y is —R₄O—, —R₄H—, —C(═O)—, —C(═O)NH—, R₄NHC(═O)NH—, or        —C(═O)NHC(═O)—; and    -   R₅ is substituted or unsubstituted alkyl selected from the group        consisting of C₈-C₄₀ linear alkyl, C₈-C₄₀ branched alkyl, C₈-C₄₀        carbocyclic alkyl, C₂-C₄₀ alkyl-substituted, phenyl,        aryl-substituted C₂-C₄₀ alkyl, and C₈-C₈₀ complex ester; wherein        the R₅ alkyl group optionally comprises one or more substituents        selected from the group consisting of hydroxy, alkoxy, and        halogen; and    -   E when present is a cross linking monomer for introducing        branching controlling molecular weight, the cross linking        monomer comprising poly functional units carrying multiple        reactive functionalization groups selected from the group        consisting of vinyl, allylic and functional mixtures thereof,        the groups A, B, C, D and E being covalently bonded one to        another in a manner selected from a random, a block or a        cross-linked copolymer format.

Amounts of “a” may range from about 0 to 10%, preferably 0.1 to about 5%by weight; amounts of “b” may range from about 10 to about 80%,preferably 15 to 60% by weight;

amounts of “c” may range from about 30 to about 85%, preferably 30 to75% by weight; amounts of “d” may range from about 1 to about 25% byweight; and amounts of “e” may range from 0 to about 5% by weight of thetotal copolymer.

Some compositions may contain water-soluble polymers in amounts of 0.005to 5% by wt.

Examples of water soluble polymers include high molecular weightpolyethylene glycols such as Polyox® WSR-205 (PEG 14M), Polyox®WSR-N-60K (PEG 45M), and Polyox® WSR-301 (PEG 90M); the carbohydrategums such as cellulose gum. Hydroxyethyl cellulose, hydroxypropylcellulose, sodium carboxymethylcellulose, methyl cellulose, ethylcellulose, guar gum, gum karaya, gum tragacanth, gum arabic, gum acacia,gum agar, and xanthan gum; modified starch granules and pregelatinizedcold water soluble starch; cationic polymer such as modifiedpolysaccharides including cationic guar available from Rhodia under thetrade name Jaguar®; cationic modified cellulose such as UCARE Polymer JR30 or JR 40 from Amerchol; N-Hance® 3000, N-Hance® 3196, N-Hance® GPX215 or N-Hance® GPX 196 from Hercules; synthetic cationic polymers suchas Merquat® 100, Merquat® 280, Merquat® 281 and Merquat® 550 sold byNalco. The water soluble polymers may be used individually or ascombinations of two or more polymers from the same or different classes.High molecular weight polyethylene glycols Polyox® WSR-301 (PEG 90M) andPolyox® WSR-N-60K (PEG 45M) and guar derivatives such as Jaguar® S,Jaguar® C17, and Jaguar® C13, and synthetic cationic polymers such asMerquat® 100 are particularly desired.

Preservatives

Personal product formulations provide good media for growth of microbes.Microbial action can be manifested in terms of hydrolysis, oxidation orreduction and may cause off-odors, changes in color, adverse change inpH, breaking of emulsions, and changes in product texture. Thus goodpreservation systems are required to prevent microbial growth, spoilingof product, and infection of skin and hair. The preservative should beeffective against Gram-negative and Gram-positive bacteria as well asfungi (molds and yeasts).

An effective preservative is a chemical agent which will preventmicrobial growth in the product, making it safe and increasing shelflife.

Optimal preservation system should provide broad spectrum activity andbe effective over the shelf-life of the product. As microorganismsmultiply in the aqueous phase of formulations, it should also bewater-soluble. Where formulations contain appreciable levels of oils,the system should favor partitioning into the aqueous phase. Ideally,the preservation system should be effective over wide pH range,colorless and safe in use. It should be non-irritating, non-sensitizingand preferably non-poisonous. Ideally, while eliminating pathogenicorganisms in the formulation while in storage, it should leave symbioticorganisms on the skin in peace after application of the formulation tothe skin, hair or mucous membrane.

Some preferred preservatives include:

-   -   1) Parabens, for example, methyl-, ethyl-, propyl-, iso-butyl-,        and butyl-paraben;    -   2) Formaldehyde-releasing preservatives, for example,        formaldehyde, quaternium-15, dimethyl-dimethyl (DMDM) hydantoin,        imidazolidinyl urea, diazolidinyl urea, sodium        hydroxymethylglycinate, and 2-bromo-2-nitropropane-1,3-diol;    -   3) Isothiazolones, such as chloromethyl-isothiozolinone (OMIT),        methyl-isothiazolinone (MIT) or benz-isothiazolinone (BIT);    -   4) Halogen-organic actives, such as idopropynyl butylcarbamate        and methyl-dibromo glutaranitrile;    -   5) Organic acids such as benzoic acid, dehydroacetic acid,        salicylic acid, lactic acid and sorbic acids;    -   6) Other, including chloroacetamide, phenyloxyethanol and        triclosan.

Additional suitable preservatives for personal care products can befound in “Preservatives for Cosmetics Manual, 2^(nd) edition”, by DavidS. Steinbens, 2006 and in “Preservatives for Cosmetics”, D. C.Steinberg, Allured Publishing Corp., ISBN #0-93170-54-5. Such agents aretypically employed at 0.1-1%, more preferably at 0.5-0.7% of thepersonal product formulation.

The organic acids noted are particularly preferred. Especially preferredare organic acids having pKa between about 4.0 and 5.5, preferably 4.0and 5.0.

No preservative is ideal for all situations. For example, parabens arerelatively non-irritant, but partition in favor of oil phase and areinactivated by some surfactants.

Formaldehyde-retaining preservatives have broad effectiveness spectrum,but are irritant and banned in some countries.

Applicants have filed a co-pending application directed to low pH basedisotropic compositions having specific preservative systems.

Compositions of that application, and certainly compositions of thisinvention having preferred pH of about 3 to 5.1, preferably willcomprise the organic acids noted above as preservative. Specifically,organic acids having pKa of 4.0 to 5.5, preferably 4.2 and 5.1 arepreferred.

More specifically compositions preferably have pH which is less than onepH unit, more preferred less than 0.5 pH unit, above the pKa of theorganic acid. Within such tight pH range, the organic acid will staylargely in undissociated form which is the form required for activityagainst microorganisms.

Thus, for example, since pKa of benzoic acid is 4.2, it is ideallysuited to be used in composition of pH less than 5.2 (as in preferredembodiments of the invention), preferably at or less than 4.7.

As indicated, benzoic acid is a preferred preservative.

Optionally, the compositions of this invention may further comprise oneor more additional ingredients. Non-limiting examples of such additionalingredients are, for example, colorants, pigments, opacifiers, fragrance(whether encapsulated or present as free-fragrance), emotive oils,vitamins and vitamin derivatives, abrasives, optical agents (includingfor example, reflective particles and interference pigments), pHadjusters, plant extracts, essential oils, preservatives, antioxidants,antimicrobials, viscosity modifiers, humectants, beard wetting agents,sensory agents, fatty acid soap, and skin and/or hair benefit agents(e.g., aloe, allantoin, panthenol, alpha-hydroxy acids, phospholipids,botanical oils, and amino acids to name a few). The selection and amountof any individual additional ingredient depends upon factors thatinclude the particular ingredient, the properties desired, and theintended use of the composition in which it is employed. For example,fragrance is typically employed in an amount of 0.1 to 3.0% by weight ofthe composition, or higher. For many compositions, the total amount ofsuch additional ingredients is 0.01 to 30% by weight, more particularly,0.1 to 15% by weight, even more particularly, 1 to 10% by weight, basedon the total weight of the composition.

In one or more embodiments, the total amount of such additional optionalingredients is 0.5 to 5% by weight. Other ingredients, for example fattyacid soap, may be present at levels up to 10% by weight, based on thetotal weight of the composition.

Compositions are aqueous based and comprise typically 30-90% by wt.water. Water is balance after all ingredients noted above are accountedfor.

Protocols

Clarity

Transparency (clarity) of a sample is measured by measuring the opticalabsorbance at wavelength of λ=550nm. The fully formulated samples (about300 μl) are added into a 96-well plate without dilution and read by amicroplate Reader (SpectraMax® 340PC, Molecular Device). An ideallytransparent sample has zero absorbance (i.e., 100% transmission). Inthis invention, a sample with absorbance of below 1.5, more preferablybelow 1, more preferably below 0.5, even more preferably below 0.2 isdefined as giving visually acceptable transparency (clarity).

EXAMPLES

Demonstration systems were constructed by weighing in predeterminedmasses of surfactants into a tared beaker. Applicants prepared examplesystems on a 50 g scale at 15% total surfactant. The desired blend ofglutamate surfactants were weighed in first, followed by anyco-surfactant. The total level of surfactant and co-surfactant wasalways 7.5 g. Then a charge of citric acid was added, calculated to besufficient to yield a final pH of about 4.5. The system was then made upto 50 g with water and heated with stirring to 75° C. After 5-15 minutesof stirring, the resulting single phase, isotropic system was removedfrom the heat and allowed to cool to room temperature. Once cool, the pHwas fine-tuned to pH 4.5 with 50% citric acid solution and water addedto replace any lost during heating. Systems were equilibrated for twoweeks at room temperature before making the observations used inconstructing the phase maps.

In order to demonstrate compositions comprising surfactant systemwherein glutamate is primary surfactant, applicants made various systemscomprising (1) mixtures of C₁₀/C₁₂ glutamate and amphoacetate; (2)mixtures of C₁₀/C_(coco) glutamate and amphoacetate; (3) mixtures ofC₁₀/C_(coco) glutamate and cocoamido propylbetaine (CAPB); (4) mixturesof C₁₀/C_(coco) glutamate and cocoamidopropyl hydroxyl sultaine (CAPHS);and (5) mixtures of C₁₀/C_(coco) glutamate and coco betaine.

Results are set forth as noted below.

Example 1

Stability Map of the lauroyl glutamate/amphoacetate system for 15% totalsurfactant and pH 4.5. Lauroyl glutamate was mixed with decanoylglutamate as indicated. Symbol I =isotropic system with absorbance valueat 550 nm below 0.2, X=two-phase system. In these systems, the leftcolumn represents % of C₁₀ relative to % of C₁₀ and C₁₂ so that, forexample, 75 represents a system in which 75% of the total glutamatepresent is C₁₀ and 25% is C₁₂. The top row is % of amphoacetate with thebalance being glutamate. Thus, 12.5 represents a system in which 87.5%of the surfactant is glutamate blend and 12.5% is amphoacetate. Thetotal surfactant present is 15% in all cases, with the remainder beingwater with a minor amount of citric acid.

TABLE 1 % decanoyl glutamate % Na lauroamphoacetate [C₁₀/(C₁₀ + C₁₂)] ×100 0 12.5 25 37.5 50 100 I I I I I 75 I I I I I 50 X X X I I 25 X X X II 0 X X X X X

It will be seen that, for this example, preferred stable, isotropiccompositions are those with a ratio of C₁₀/C₁₂ acyl glutamate of about1/3 and higher and with a ratio of lauroamphoacetate/acyl glutamate ofabout 1/1.7 and higher (up to 1/1). To ensure good foam performance andminimize costs, the ratio of C₁₀/C₁₂ acyl glutamate should be 1/1 andlower (preferably above 1/3) and the ratio of lauroamphoacetate/acylglutamate should be 1/1 or lower.

Example 2

Stability Map of the cocoyl glutamate/amphoacetate system for 15% totalsurfactant and pH 4.5. Cocoyl glutamate was mixed with decanoylglutamate as indicated. Symbol I=isotropic system with absorbance valueat 550 nm below 0.2, X=two-phase system. Percentages are measured asnoted in Table 1 of Example 1.

TABLE 2 % decanoyl glutamate % Na lauroamphoacetate [C₁₀/(C₁₀ +C_(coco))] × 100 0 12.5 25 37.5 50 50 I I I I X 37.5 I I I I X 25 X I II X 0 X X I I I

It will be seen that preferred stable, isotropic compositions are thosewith a ratio of C₁₀/C_(coco) acyl glutamate of about 1/3 and higher andwith a ratio of lauroamphoacetate/acyl glutamate of about 1/7 andhigher. To ensure good foam performance, minimize costs, and observe anenhanced viscosity, the ratio of Cio/C_(coco) acyl glutamate should be1/1 and lower (preferably about 1/3 and above) and the ratio oflauroamphoacetate/acyl glutamate should be 1/1.7 or lower.

Example 3

Stability Map of the cocoyl glutamate/CAPB system for 15% totalsurfactant and pH 4.5. Cocoyl glutamate was mixed with decanoylglutamate as indicated. Symbol I =isotropic system with absorbance valueat 550 nm below 0.2, X=two-phase system. Percentages are measured asnoted in Table 1.

TABLE 3 % decanoyl glutamate % CAPB [C₁₀/(C₁₀ + C_(coco))] × 100 0 12.525 37.5 50 50 I I X X X 37.5 I X X X X 25 X X X X X 0 X X X X X

As seen from Examples 1-3, when we use a mixture of C₁₀ and C_(coco),(Table 2) compared to mixture of C₁₀ and C₁₂ (Table 1), an isotropicregion is achieved using lower amounts of C₁₀ glutamate. That is, lessC₁₀ is needed to achieve soluble region (which also helps with latherproduction). Systems are glutamate plus co-surfactant (e.g.,amphoacetate or cocoamidopropylbetaine). Non-ionic surfactant is apreferred co-surfactant in a glutamate/co-surfactant system. Whenco-surfactant used is CAPB rather than amphoacetate (Table 3 versusTable 2), some solubility benefit at lesser level of C₁₀ is lost. Evenwhere solubility is lost, however, benefits of low pH (for alternativepreservation systems) and foam from using high glutamate surfactantchassis are retained.

Example 4

Stability Map of the cocoyl glutamate/cocoamidopropyl hydroxyl sultaine(CAPHS) system for 15% total surfactant and pH 4.5. Cocoyl glutamate wasmixed with decanoyl glutamate as indicated. Symbol I =isotropic systemwith absorbance value at 550 nm below 0.2, X=two phase system.Percentages are measured as noted in Table 1.

TABLE 4 % decanoyl glutamate % CAPHS [C₁₀/(C₁₀ + C_(coco))] × 100 0 512.5 25 37.5 50 50 I I I I I I 37.5 I I I I I I 25 X I I I I I 0 X X X XI I

It will be seen that preferred stable, isotropic compositions are thosewith a ratio of C₁₀/C_(coco) acyl glutamate (using CAPHS, lessco-surfactant is needed to obtain isotropic region compared to certainother co-surfactants, e.g., CAPB or amphoacetate) of about 1/7 andhigher and with a ratio of CAPHS/acyl glutamate of about 1/19 andhigher. To ensure good foam performance, minimize costs, and observe anenhanced viscosity, the ratio of C₁₀/C_(coco) acyl glutamate should be1/1 and lower and the ratio of CAPHS/acyl glutamate should be 1/1 orlower.

Example 5

Stability Map of the cocoyl glutamate/coco betaine system for 15% totalsurfactant and pH 4.5. Cocoyl glutamate was mixed with decanoylglutamate as indicated. Symbol I—isotropic system with absorbance valueat 550 nm below 0.2, X=two phase system. Percentages are measured asnoted in Table 1.

TABLE 5 % decanoyl glutamate % cocoyl betaine [C₁₀/(C₁₀ + C_(coco))] ×100 0 5 12.5 25 37.5 50 50 I I I I I I 37.5 I I I I I I 25 X I I I I I 0X X I I I I

It will be seen that preferred stable, isotropic compositions are thosewith a ratio of C₁₀/C_(coco) acyl glutamate of about 1/7 and higher andwith a ratio of coco betaine/acyl glutamate of about 1/19 and higher(less co-surfactant needed to obtain isotropic regions compared to useof certain other co-surfactants). To ensure good foam performance,minimize costs, and observe an enhanced viscosity, the ratio ofC₁₀/C_(coco) acyl glutamate should be 1/1 and lower and the ratio ofcoco betaine/acyl glutamate should be 1/1 or lower.

As seen from Examples 2, 4 and 5, when we use a mixture of C₁₀ andC_(coco) glutamates along with a co-surfactant chosen from the preferredlist of amphoteric surfactants, a broad, isotropic, stable regionresults. More specifically, blending shorter chain length glutamates(decanoyl glutamate) with longer chain length glutamates (cocoylglutamate) yields isotropic systems at pH 4.5 in which glutamatecomprises 100% of the surfactant system. Further, addition of preferredamphoteric co-surfactants to glutamate blends results in isotropicsystems in which glutamate comprise ≧50% of the surfactant system and100% of the total anionic surfactant while allowing for a glutamateblend richer in longer chain lengths, which enhances foaming. Again,even where benefit agents in final system may form anisotropiccompositions, foam benefits are retained.

Examples 6-8

For Examples 6-8, finished formulations were prepared by adding thesurfactants, starch, and 70% of the free water into a tared vesselimmersed in a water bath and with overhead mixing. The components arestirred until uniformly mixed and then the stirring continued as thewater bath temperature is raised to 70° C. Once at temperature, theJaguar (predispersed in glycerin) and PEG are added along with thecitric acid. Cooling is initiated and the other components added oncethe water bath reaches 35° C. The final pH and water content are thenadjusted.

Example 7 % % on active Example 6 100% Example 8 Chemical/ as % on 100%active % on 100% Trade Name supplied active basis basis active basisWater 100 84.27 83.85 79.35 Puregel B990 100 0.00 0.00 4.5 (modifiedstarch; thickener) Lauroyl 100 6.60 6.60 0.00 Glutamate Cocoyl Glutamate100 0.00 0.00 6.60 Na Lauroyl 30 0.00 0.00 0.00 Sarcosinate Sodium 205.40 5.40 5.40 lauroamphoacetate Jaguar C-14 100 0.3 0.3 0.3 Glycerin100 2.00 2.00 2.00 PEG-45M 100 0.05 0.05 0.05 Citric acid 50 1.25 1.251.25 Sodium benzoate 100 0.00 0.5 0.5 (preservative) butylated 100 0.000.00 0.00 hydroxytoluene (BHT) Methylisothiazolinone 9.5 0.01 0.00 0.00(MIT) (preservative) Glydant Plus Liquid 20 0.07 0.00 0.00(preservative) EDTA 39 0.05 0.05 0.05 (ethylenediamine tetraacetic acid)(sequestrant) Total 100 100 100 pH 4.5 4.5 4.5

Example 6 is typical of a conventional preservation system, which can beused over a wide pH range but whose application is regionallyrestricted. In contrast, Example 7 illustrates a preservation systemwhich is preferred in those regions but which will only function at pH5.0 and below. The example formulation provides an effective productform in which to practice this preservation system. Both examplesyielded stable, isotropic, single phase systems. Example 8 is an exampleof a finished formulation which contains optional benefiting ingredients(Puregel® B990 in this case, a starch thickening agent) which render thefinal system anisotropic, though still stable against physical phaseseparation.

Examples 9-11

For Examples 9 -11, finished formulations were prepared as described forExamples 6-8.

Example Example Example 9 10 11 % on % on % on % 100% 100% 100%Chemical/ active as active active active Trade Name supplied basis basisbasis Water 100 77.99 74.75 64.44 (modified polyacrylate; 34 0.5 0.5 0.0thickener)¹ Puragel B990 (modified 100 0.0 0.0 4.50 starch thickener)Carbopol 980 100 0.0 0.0 0.6 Decanoyl 100 4.39 4.39 0.0 Glutamate CocoylGlutamate 23 4.39 4.39 6.6 Na Lauroyl Sarcosinate 30 0.95 0.95 0.0Cocamidopropyl hydroxy 40 5.28 6.00 0.0 sultaine Sodium 28 0.0 0.0 5.40lauroamphoacetate Jaguar C-14 100 0.0 0.1 0.30 Glycerin 100 5.00 2.006.0 PEG-14M 100 0.0 0.0 0.5 PEG-45M 100 0.05 0.05 0.0 Soybean Oil 1000.0 3.0 0.0 Hydrogenated Soybean 100 0.0 2.0 0.0 Oil Petrolatum 100 0.00.0 8.75 Polybutene (H-300) 100 0.0 0.0 0.5 Citric acid 50 1.32 1.321.15 Sodium benzoate 100 0.00 0.5 0.0 (preservative) butylatedhydroxytoluene 100 0.00 0.00 0.10 (BHT) Methylisothiazolinone 9.5 0.010.00 0.01 (MIT) (preservative) Glydant Plus Liquid 20 0.07 0.00 0.0(preservative) EDTA (ethylenediamine 39 0.05 0.05 0.05 tetraacetic acid)(sequestrant) Fragrance 100 0.0 0.0 1.10 Total 100 100 100 pH 4.8 4.84.8 ¹This is a copolymer which is the polymerization product of (byweight of total polymer) (a) about 40 to 70% ethyl acrylate; (b) 20 to50% methacrylic acid; (c) 0.1 to 3% maleic anhydride and; (d) 2 to 15%of an associative monomer (for example, Component D of Formula V definedabove).

Example 9 is typical of a conventional preservation system, which can beused over a wide pH range but whose application is regionallyrestricted. In contrast, Example 10 illustrates a preservation systemwhich is preferred in those regions but which will only function at pH5.0 and below. The example formulation provides an effective productform in which to practice the preservation system. Both examples yieldedstable, isotropic, single phase surfactant chassis. Example 10 is anexample of a finished formulation which contains optional benefitingingredients (soybean oil and hydrogenated soybean oil in this case, anemollient oil) which render the final system anisotropic, though stillstable against physical phase separation. Similarly, Example 11 is anexample of a finished formulation which contains optional benefitingingredients (petrolatum and polybutene, an emollient oil and sensorymodifier, respectively) which render the final system anisotropic,though still stable against physical phase separation. ¹ This is acopolymer which is the polymerization product of (by weight of totalpolymer) (a) about 40 to 70% ethyl acrylate; (b) 20 to 50% methacrylicacid; (c) 0.1 to 3% maleic anhydride and; (d) 2 to 15% of an associativemonomer (for example, Component D of Formula V defined above).

1. Cleansing composition comprising: a) 0.5 to 35% by wt. totalcomposition of a surfactant system comprising anionic surfactantcomprising salt of acyl glutamate, wherein salt of acyl glutamate ispresent at 50 wt % or more of all surfactant present, and wherein thesurfactant system further comprises 0 to 20% by wt. total composition ofa co-surfactant, wherein co-surfactant are surfactants which are notanionic, selected from the group consisting of nonionic, cationic,amphoteric surfactants and mixtures thereof; b) 0% to 30% by wt. totalcomposition of a water-soluble or oil-soluble skin or hair benefitagent, not being a surfactant; and c) water wherein pH is 5.5 or lower,wherein salt of glutamate comprises a mixture of C₁₀ and C_(coco)glutamate, wherein the mixture of C₁₀ and C_(coco) has a C₈-C₁₀ chainlength distribution wherein C₈-C₁₀ is present in an amount of more than13%, or salt of glutamate comprises a mixture of C₁₀ and C₁₂ glutamate,wherein the ratio of C₁₀ to C12 is at least 1/5, wherein the salt ofglutamate has a cation which is sodium or potassium.
 2. A compositionaccording to claim 1, wherein the composition is clear, wherein clear isdefined by absorbance value of 1.0 or below when measured at wavelengthof 550 nm, adding 300 μl into a 96-well plate without dilution.
 3. Acomposition according to claim 1, comprising 0.5 to 15% co-surfactant.4. A composition according to claim 1, wherein co-surfactant comprisesan amphoteric surfactant.
 5. A composition according to claim 1 furthercomprising 0.1% to 5% by wt. benefit agent.
 6. A composition accordingto claim 1 wherein said benefit agent is an oil-soluble emollient ormoisturizing oil.
 7. A composition according to claim 1 wherein pH ofcomposition is 3.5 to 5.5.
 8. A composition according to claim 7 whereinpH is 4.0 to 5.5.
 9. A composition according to claim 8 wherein pH is 4to 5.1.
 10. A composition according to claim 1 additionally comprisingstructurant.
 11. A composition according to claim 10 which comprises astructurant having formula:

wherein a, b, c, d and e represent the percentage by weight that eachrepeating unit monomer is contained within the copolymer; A is apolyacidic vinyl monomer selected from the group consisting of maleic,fumaric, itaconic, citraconic and acid combinations thereof andanhydrides and salts thereof; and B is acrylic or methacrylic acid or asalt thereof; C is a C₁-C₈ ester of acrylic acid or methacrylic acid; Dis an associative monomer of formula (II)

wherein each R₂ is independently H, methyl, —C(═O)OH, or —C(=O)OR₃; R₃is a C₁-C₃₀ alkyl; T is —CH₂C(═O)O—, —C(═O)O—, —O—, —CH₂O—, —NHC(═O)NH—,—C(═O)NH—, —Ar—(CE₂)_(z)—NHC(═O)O—, —Ar—(CE₂)_(z)—NHC(═O)NH—, or—CH₂CH₂NHC(═O)—; Ar is divalent aryl; E is H or methyl; z is 0 or 1; kis an integer in the range of 0 to 30; and m is 0 or 1; with the provisothat when k is 0, m is 0, and when k is in the range of 1 to 30; m is 1,(R₄O)_(n) is polyoxyalkylene, which is a homopolymer, a randomcopolymer, or a block copolymer of C₂-C₄-oxyalkylene units, wherein R₄is C₂H₄, C₃H₆, C₄H₈, or a mixture thereof, and n is an integer in therange of 5 to 250; Y is —R₄O—, —R₄H—, —C(═O)—, —C(═O)NH—, ═R₄NHC(═O)NH—,or —C(═O)NHC(═O)—; and R₅ is substituted or unsubstituted alkyl selectedfrom the group consisting of C₈-C₄₀ linear alkyl, C₈-C₄₀ branched alkyl,C₈-C₄₀ carbocyclic alkyl, C₂-C₄₀ alkyl-substituted, phenyl,aryl-substituted C₂-C₄₀ alkyl, and C₈-C₈₀ complex ester; wherein the R₅alkyl group optionally comprises one or more substituents selected fromthe group consisting of hydroxy, alkoxy, and halogen; and E when presentis a cross linking monomer for introducing branching and controllingmolecular weight, the cross linking monomer comprising polyfunctionalunits carrying multiple reactive functionalization groups selected fromthe group consisting of vinyl, allylic and functional mixtures thereof,the groups A, B, C, D and E being covalently bonded one to another in amanner selected from a random, a block or a cross-linked copolymerformat.
 12. A composition according to claim 1 further comprisingimmiscible benefit agent.
 13. A composition according to claim 1 whereinsalt of acyl glutamate is selected from the group consisting of C₁₀, C₁₂and C_(coco) glutamate and mixtures thereof, co-surfactant isamphoacetate and ratio of amphoacetate to salt of glutamate is 1/7 andhigher.
 14. A composition according to claim 13, wherein ratio is 1/7 to1/1.
 15. A composition according to claim 1 wherein salt of glutamate isselected from the group consisting of C₁₀, C₁₂ and C_(coco) glutamateand mixtures thereof, co-surfactant is selected from the groupconsisting of betaine, sultaine and mixtures thereof and ratio ofco-surfactant to glutamate of 1/19 and higher.
 16. A compositionaccording to claim 15, wherein ratio is 1/19 to 1/1.